HashMap的七种遍历方式

来一个HashMap,简简单单赋值

HashMap<String, String> hashMap = new HashMap<>();
        hashMap.put("hh","21");
        hashMap.put("ll","22");
        hashMap.put("kk","23");
        hashMap.put("jj","24");

方式一 ：keySet和增强for

        Set<String> keys = hashMap.keySet();
        for (String key : keys) {
            System.out.println(key+"=="+hashMap.get(key));
        }

方式二 ：ikeySet和terator

        Set<String> keys = hashMap.keySet();
        Iterator<String> iterator = keys.iterator();
        while (iterator.hasNext()){
            String key = iterator.next();
            System.out.println(key+"=="+hashMap.get(key));
        }

方式三： entrySet和iterator

        Set<Map.Entry<String, String>> entries = hashMap.entrySet();
        Iterator<Map.Entry<String, String>> entryIterator = entries.iterator();
        while (entryIterator.hasNext()){
            Map.Entry<String, String> entry = entryIterator.next();
            System.out.println(entry.getKey()+"==="+entry.getValue());
        }

方式四：entrySet和增强for

        Set<Map.Entry<String, String>> entries = hashMap.entrySet();
        for (Map.Entry<String, String> entry : entries) {
            System.out.println(entry.getKey()+"==="+entry.getValue());
        }

方式五：lambda表达式

        hashMap.forEach((t1,t2)-> System.out.println(t1+"=="+t2));

方式六：entrySet和顺序流

  hashMap.entrySet().stream().forEach((entry)-> System.out.println(entry.getKey()+"=="+entry.getValue()));

方式七：entrySet和并行流

hashMap.entrySet().stream().parallel().forEach((entry)-> System.out.println(entry.getKey()+"=="+entry.getValue()));

我知道的暂时就这么多啦。。。。